Field of the Invention
The invention relates to a power circuit, and more particularly to a current source circuit.
Description of Related Art
In design of an analog circuit, a reference voltage or reference current is required. The reference voltage provides an operation criterion, and the analog circuit is, for example, an oscillator, a delay cell, or the like. Moreover, depending on the process, characteristics of the analog circuit may drop, and the design of the analog circuit is affected. In addition, as the process evolves, the number of transistors contained in a unit area becomes increasingly larger, such that an increasingly larger amount of thermal energy is generated during operation of the circuit, and thus the temperature of the circuit becomes increasingly higher. Due to the temperature rise, characteristics of devices in the integrated circuit may deteriorate to cause instability of the performance of the circuit. Therefore, if a bias current which is stable and not affected by temperature is employed in the analog circuit, the difficulty in designing the circuit may be reduced.